U.S. Pat. Nos. 3,822,188, 3,808,234, and 3,864,492 all to Fager et al. disclose the fermentation of .DELTA..sup.9 -THC (1-hydroxy-3-n-pentyl-6,6,9-trimethyl-6a,7,10,10a-tetrahydrodibenzo[b,d]py ran) with such micro-organisms as Cunninghamella blakesleeana, Streptomyces viridoilavus, Mucor parasiticus, Aspergillus fonsecaeus, etc. to produce the corresponding 4'-hydroxy derivatives; i.e., compounds in which the n-pentyl side-chain is oxidized on its penultimate carbon by the action of the micro-organism. The compounds thus produced are said to be anti-depressants. Vidic et al., U.S. Pat. No. 3,897,306, oxidize an isomer (.DELTA..sup.8 -THC) with Streptomyces lavendulae or with Peliculiaria filamentosa to produce a quite different compound in which the C-7 carbon is hydroxylated to yield a 7-hydroxy-.DELTA..sup.8 -THC derivative. Robertson, et al., Biomedical Mass Spectrometry, 1975(2) 266-271 find that exposure of .DELTA..sup.9 -THC, .DELTA..sup.8 -THC, cannabinol, and cannabidiol to the fungus Syncephalastrum racemasum yields products which carry a hydroxyl group on the penultimate carbon atom.
A series of 1-hydroxy-3-alkyl-6,6a,7,8,10,10a-hexahydro-9H-dibenzo[,d]pyran-9-ones have been found by Archer to be useful as anti-depressant, anti-anxiety, sedative, and analgesic drugs--see U.S. Pat. No. 3,928,598. Compounds of this structure were first synthesized by Fahrenholtz, et al., J. Am. Chem. Soc., 88 2078 (1966), 89, 5934 (1967), as intermediates for the preparation of .DELTA..sup.8 - or .DELTA..sup.9 -THC. (See also U.S. Pat. No. 3,507,885 and U.S. Pat. No. 3,636,058). The same group of .DELTA..sup.8 - and .DELTA..sup.9 -THC compounds are disclosed by Petrzilka in U.S. Pat. No. 3,873,576.